Reclining and stretching chairs are not new per se. Chairs that recline have been manufactured for many years. With the development of anatomical and ergonomic engineering, reclining chairs have evolved to be more comfortable and more versatile.
Various chairs have been designed that provide the capability to stretch and strengthen muscles. For example, U.S. Pat. No. 3,561,772 discloses a lightweight, reclining and exercising device that includes pivoting panels that are connected with a fixed pivot member. The chair is specifically designed to stretch and strengthen the back muscles. U.S. Pat. No. 3,641,995 shows an exercising chair that also includes a fixed pivot axle between a seat and a back section and is used to exercise the back and leg muscles.
There are also numerous chairs manufactured that are primarily designed to recline and be comfortable. Many of the existing recliners include interconnected platform members that are adjustable in different ways. In U.S. Pat. No. 3,934,932 the angle between an interconnected seat and back platform is adjusted with a frictional coupler that is attached to the seat platform and a tubular portion of the base. U.S. Pat. No. 4,790,599 shows a chair having a fixed angle between the chair and the seat platform. The combined chair and seat platform swings about a raised pivot point and is adjusted along a fixed track positioned on the base of the chair.
What is needed is a chair that can be moved by the user through a range of different therapeutic and generally comfortable motions including tilting, rocking and angular changing between platform components on the body platform assembly. The chair should allow the person sitting, reclining or stretching in the chair to be able to change the angular position of the platform components freely by shifting their weight. Ideally, the chair should be easy to lock in any desired position.